Are IDT oligos desalted (salt-free)?
Oligonucleotides provided by IDT are desalted—free of added salt. First, no inorganic salts, such as sodium or magnesium, are used when DNA is synthesized chemically. Our standard desalting step refers to the removal of small organic molecules left over from synthesis.
The desalting process does remove the majority of these organic molecules, though trace amounts can still be present in a shipped oligo.
For the most demanding applications sensitive to even trace amounts of salts, e.g., NMR or crystallography, upon receipt we recommend dialyzing your oligos or using a size exclusion column as a clean-up step.